A question; in general would you agree that the issue starts gradually at some point and then gets progressively worse?

Not trying to put words in your mouth , just thinking in one direction and one step at a time if that makes sense..

Cheers max

Hi Max. My issue started with the slow idle / stalling. However, it was never a bad as the video on this thread. I could always restart my bike after it stalled, and it would run fine at a higher RPM - it just didn't want to idle. This issue went away by itself, and then the high idle (1,500 rpm) started about two months later. This lasted about 1 - 2 months. After a WFO run in the desert (started at low RPM in 4th gear to make a pass with a passenger on back and ran through the gears while wide open, but never exceeding 6,000 RPM), the high RPM idle issue cured itself also, and has never returned. About 2,000 trouble-free miles later the low idle / stalling has returned. I can keep the bike from stalling by blipping the throttle - it runs fine as soon as the RPM is increased above about 3,000. This low RPM / stalling comes and goes at will now. I will put my bike away when the problem occurs, and start it up the next day and it will run perfectly. I believed that the high RPM issue was brought on by slow, stop & go riding, when the engine got hot. But I have seen no connection to the riding conditions or temperature for the low RPM / stalling. In my opinion, the fuel mixture is leaning out when the low RPM condition occurs. I can sense a different response when I blip the throttle when this condition is happening that sure reminds me of a cold starting condition with a carbureted bike. Do you think there is any connection to the level of oil in the bike and this problem? Is it possible that excess oil somehow causes the EOT sensor to send a bad signal to the ECM? Also, my bike experienced poor low speed running from the day I bought it, which was finally cured by the TPS reset (I am extremely sensitive to how my bike runs, and the dealer said it was running fine, but I felt an immediate improvement after the TPS reset.) My bike has never shown an error code. Thank you so much for digging into this - I just don't have the time, or experience to diagnose electrical problems on my own.

(12-05-2017 05:51 PM)pdedse Wrote: But if it were vacuum leak related, wouldn't the high idle happen consistently, as in "all the time"? I've had high and low idle on the same ride. Stop, turn off engine, restart, problem goes away, sometimes it doesn't.

May depend upon the nature of the leak:
1. intake boot may be affected by thermal expansion
2. cracked/loose hose may be affected by movement
3. cracked fitting (4 way or 5 way) may be affected by heat and/or movement. Small crack = high idle...crack opens and bike barely idles.

Not saying this is the issue, but worth checking:
a. Snug clamp bolts
b. Check hoses are not hardened and pushjed all the way on.
c. inspect fittings
d. apply unlit propane and listen for idle speed change

(12-05-2017 09:14 PM)max Wrote: Just some pics to show how i tested the rpm eot relationship.

first pic is what is connected and type of connectors ( everything is wired in parallel )

second is with engine lukewarm r eot = 1000 ohm 3.468 v and 1340 rpm.

third is engine warmed up just enough for the rpm to settle at 1050 rpm at 2.17 v at 371 ohm.

So the point where the engine settles at 1050 rpm appears to be 2 volts across the eot sensor,

Good info and great pics!

(12-05-2017 08:04 PM)max Wrote: Hi again doc, some more info and a video.

Interestingly i could not get the engine to idle below 1050 rpm? ( low rpm issue ).

Great visual depiction of correlation of lowering EOT voltage with lowering of idle speed. In the first test as both were dropping, then the EOT voltage climbed , which should indicate oil colder, instead of warming up.
Somehow added resistance is getting into the EOT-ECU circuit:
Air pocket at EOT possible???

I just got home from a long meeting with some paperwork to do tonight, so I am not completely focused, but my initial thinking is that your video indicates that it is NOT
A. an internal ECU / ECU program issue
B. not a vacuum issue
C. Not an IAC issueon your bike.

There are many different bikes, both manufacturer and model, with EFI idle issues...there may be many different causes.

This allows present and future member to evaluate (albeit carefully), if the need arises.

In the automotive world TPS failures are somewhat common, especially above 100,000 miles and typically cause a limp mode. I would expect few issues on a bike with much lower miles, but still very surprised that a TPS cannot be purchased separately.

Doc,
U R absolutely right, TPS is very simple device and should be able to purchase separately as well as ISCSV and stepper motor....Honda is taking huge advantage of customers.
More than certain Honda does not make above mentioned parts...most likely Keihin, ND, Kefico, Mitsubishi... or some others manufactures...
If we dig, we can find supplier..
But as we said = diagnose faulty part before replacement
...and if you need further assistance, drop me a line...forum or PM..perhaps I can help

I have had the low idle issue twice on my 2013 with 50k miles. Both times were stop and go traffic with temps above 90*F.

Both times simply shutting off the kill switch, turning it back on, and re-starting the bike fixed it temporarily. The problem will creep up again after 10-15 minutes if traffic remained bad but stayed away if traffic started moving. I haven't had the problem again after the temps went below 90*F.

(12-06-2017 07:42 AM)kennyw Wrote: I have had the low idle issue twice on my 2013 with 50k miles. Both times were stop and go traffic with temps above 90*F.

Both times simply shutting off the kill switch, turning it back on, and re-starting the bike fixed it temporarily. The problem will creep up again after 10-15 minutes if traffic remained bad but stayed away if traffic started moving. I haven't had the problem again after the temps went below 90*F.

I have not had the high idle issue.

Heat can affect electronics.
If a heat related issue is suspected of an electronic device, but it is intermittent, it can oft be replicated using a hair dryer.

Does the FSM detail what actions the ECU takes under higher operating temperatures?...or if the EOT is signaling the ECU that it is hotter than it actually is.

(12-05-2017 11:05 PM)Dave Wrote: ...My issue started with the slow idle / stalling. However, it was never a bad as the video on this thread. I could always restart my bike after it stalled, and it would run fine at a higher RPM - it just didn't want to idle. This issue went away by itself, and then the high idle (1,500 rpm) started about two months later. This lasted about 1 - 2 months. After a WFO run in the desert (started at low RPM in 4th gear to make a pass with a passenger on back and ran through the gears while wide open, but never exceeding 6,000 RPM), the high RPM idle issue cured itself also, and has never returned. About 2,000 trouble-free miles later the low idle / stalling has returned. I can keep the bike from stalling by blipping the throttle - it runs fine as soon as the RPM is increased above about 3,000. This low RPM / stalling comes and goes at will now.

1. Is IAC clean?

2. Have connections to IAC and EOT been disconnected and reconnected to "wipe" the contacts to insure a good connection?

3. Plugs read?...burning clean?

4. Check for vacuum leak (from post 570: I had a failure to idle issue on my V7II, first experienced at 8,000 feet altitude, ~5 months in service and 6,000 miles. It required throttle to maintain idle, even after returning to 2,200 feet elevation. Cured by tightening band around rubber from single throttle body to intake manifold.) It was a quick restart when it died, also.

5. Connections to all other sensors (O2, IAT, CKP) disconnected and reconnected to "wipe" the contacts to insure a good connection? On the XLForum, 07 up Sportsters have solved several issues by cleaning the CKP connection, which is down low and exposed to road grime.

I haven't checked, but agree this is a very good idea. Plan to do this when I get around to checking my valve clearances.

2. Have connections to IAC and EOT been disconnected and reconnected to "wipe" the contacts to insure a good connection?

Haven't checked the IACV (will do), but have replaced the EOT sensor, and have had it disconnected and reconnected several times.

3. Plugs read?...burning clean?

Checked them once, the first time the problem surfaced, and they looked perfect.

4. Check for vacuum leak (from post 570: I had a failure to idle issue on my V7II, first experienced at 8,000 feet altitude, ~5 months in service and 6,000 miles. It required throttle to maintain idle, even after returning to 2,200 feet elevation. Cured by tightening band around rubber from single throttle body to intake manifold.) It was a quick restart when it died, also.

Haven't checked, but this is a good suggestion and will do this. Can I get at all four without having to disassembly a whole lot of things - like removing the gas tank?

5. Connections to all other sensors (O2, IAT, CKP) disconnected and reconnected to "wipe" the contacts to insure a good connection? On the XLForum, 07 up Sportsters have solved several issues by cleaning the CKP connection, which is down low and exposed to road grime.

(12-07-2017 08:10 PM)Dave Wrote: Haven't checked [throttle body to intake hose clamps], but this is a good suggestion and will do this. Can I get at all four without having to disassembly a whole lot of things - like removing the gas tank?

No need to remove anything.
I used a 8 mm 6 point socket on an extension to check the snugness on mine. Two of the innermost clamps had a bit of an angle, so a universal joint was helpful. Not good (on the life of the rubber) or necessary to overtighten, just "snug". For me that is two fingers close to the ratchet on a 1/4" drive.

To check the 4 way and 5 way vacuum fittings (3/16"?), it may require tank removal, but personally I would prefer to not deal with the fuel quick disconnect, if not necessary. A long screwdriver, flashlight and gentle probing will probably detect a crack, if present.

Wish I had not given away my vacuum gauge, then I could advise a normal vacuum read.

Doc, I just got a DigiSync digital manometer to use to sync the throttle valves on my ST. I could use that to read vacuum, BUT, I fired up the Healtech software and it gives MAP reading in psig (or Kpa-user selectable)

I’ll have to fire up the CB and see what it reads. Its raining pretty good now so maybe later.

(12-08-2017 12:18 PM)popgun Wrote: Doc, I just got a DigiSync digital manometer to use to sync the throttle valves on my ST. I could use that to read vacuum, BUT, I fired up the Healtech software and it gives MAP reading in psig (or Kpa-user selectable)

I’ll have to fire up the CB and see what it reads. Its raining pretty good now so maybe later.

Got a call from Honda Customer Service today! To refresh: back in late October or early November--I can't remember which--I took my bike to the dealer with letter in hand explaining the problem, but couldn't get the bike to "act up", so I decided against leaving bike with them. A few days later, talked to the SM who said without any check engine light and unable to duplicate the high/low idle issue, that it likely would be difficult for them to diagnose. He suggested I write my letter to Honda CS which I did and left a phone message about two weeks ago.

Back to my call: they wanted to know if I had the dealer look at the problem. I said "no" for the reasons stated above. We talked a good 20 minutes about the problem, the forum responses here, I mentioned a few specific cases. She said for anything to happen, the bike will need to be looked at by a dealer. No promises can be made, but she offered the hope that Honda will respond at times even when bikes are out of warranty. But, I need to the bike to break bad. Last 4 rides of 1-2 hrs riding, no real problem with idle, except just a dip below to 800-900 for a minute. Turn off engine, restart and all good. Nothing like before. But temps are down to 35-50 degrees, so that may play a part.

I asked about Service Bulletins and Recalls, of course nothing, but that she said they need to hear from owners with the problem. The answer is going to be contact dealer, but at least it will be better documented. In time, maybe that produces a response from Honda.

I told her that based on what my dealer said--that they need to replicate the problem--maybe when it warms up--I'll give them one go at it to see if they can determine anything. Anyway...at least they called as a result of me sending in my letter.